feat(hooks): add BeforeOp hook and fix BeforeScan row-security gap

Adds a BeforeOp HookType across resolvespec, restheadspec, websocketspec,
mqttspec, and funcspec that fires before every SQL operation (read,
create, update, delete, scan/query) via a new ExecuteBeforeOp helper.

Also closes a row-level-security gap: resolvespec registered a BeforeScan
hook for ApplyRowSecurity but never fired it, and websocketspec/mqttspec
had no BeforeScan hook point at all, so row security was never applied
to their queries. BeforeScan now fires right before the actual scan in
all three, with the (possibly hook-modified) query used for execution.

pkg/websocketspec/hooks.go

@@ -35,6 +35,11 @@ const (
 	// AfterDelete is called after a delete operation
 	AfterDelete HookType = "after_delete"
 
+	// BeforeScan is called right before a read query is executed against the database,
+	// after all filters/sort/pagination have been applied. Use this for row-level
+	// security that needs to modify the query (stored in HookContext.Metadata["query"]).
+	BeforeScan HookType = "before_scan"
+
 	// BeforeSubscribe is called before creating a subscription
 	BeforeSubscribe HookType = "before_subscribe"
 	// AfterSubscribe is called after creating a subscription
@@ -54,6 +59,11 @@ const (
 	BeforeDisconnect HookType = "before_disconnect"
 	// AfterDisconnect is called after a connection is closed
 	AfterDisconnect HookType = "after_disconnect"
+
+	// BeforeOp fires immediately before every SQL operation (read, create, update, delete).
+	// Unlike BeforeHandle, which fires once before operation dispatch, BeforeOp fires at each
+	// individual SQL-operation hook point, so it runs once per statement executed.
+	BeforeOp HookType = "before_op"
 )
 
 // HookContext contains context information for hook execution
@@ -197,6 +207,16 @@ func (hr *HookRegistry) Execute(hookType HookType, ctx *HookContext) error {
 	return nil
 }
 
+// ExecuteBeforeOp executes the BeforeOp hook followed by the given SQL-operation hook
+// (BeforeRead, BeforeCreate, BeforeUpdate, or BeforeDelete). BeforeOp always runs first
+// so it can observe/veto every SQL operation regardless of type.
+func (hr *HookRegistry) ExecuteBeforeOp(hookType HookType, ctx *HookContext) error {
+	if err := hr.Execute(BeforeOp, ctx); err != nil {
+		return err
+	}
+	return hr.Execute(hookType, ctx)
+}
+
 // HasHooks checks if any hooks are registered for a hook type
 func (hr *HookRegistry) HasHooks(hookType HookType) bool {
 	hooks, exists := hr.hooks[hookType]